Method of and apparatus for manufacturing concrete pipes



Dern 27, 1927.

A. HGRTEN METHOD OF AND APPARATUS FOR MANUFACTURING CONCRETE PIPES mea Feb. 19. 192s wav/inw@ Patented Dec. 27, 1927.

UNITED STATES ALPHONS HRTEN, OF BERLIN-WILMERSDORF, GERMANY.

METHOD or AND ArrAaA'rUs Fon MANUFACTURING CONCRETE PIPES.

Application led February 19, 1926, Serial No. 89,483, and in Germany February 23, 1925.

My invention relates to improvements in the method of and apparatus for manufacturing concrete pipes such as are'used for conducting liquids and gases. My improved method may be used for manufacturing reinforced concrete pipes having va very smooth inner surface.

One of the objects of the improvements is to provide a method by means of which pipes are produced which are free of fine cracks interfering with the strength of the pipe and causing leakage of the Huid. With, this object in view my invention consists in manufacturing the Wall of the pipe in diffrent layers, one layer being first applied to a suit'- able core by iinging or squirting soft concrete onto a rotary core, allowing the said concrete to set, and thereafter flinging or squirting another layer oit' soft concrete onto the inner layer previously produced on4 the core. Ordinarily each layer has a thickness substantially equal to one Ahalf the desired thickness of the wall of the pipe. In the manufacture of re-inforced concrete pipes I place re-inforcing iron in the form of a net or a coil of Wire or strip iron on the surface of the set inner layer, and I apply the second or outer layer on the said re-inforcing iron and the inner layer. f

Foreconomical reasons, and more particularly when manufacturing the pipeintwo layers, it is important that the setting of the concrete becompleted Within a short period of time in order that the cores the cost of which is comparatively high may be used hfor manufacturing further pipes. Further it is important to carry out the method in such away that the inner surface of the inner layer be as smooth as possible and that the core can readily befremoved `fromgthe said pipe. Therefore my method includes aafstep inv which the concrete is rapidly set and it makes use of cores insuring a smooth inner surfaceof the complete ipe.

In my improved met lod the concrete is flung-or squlrted on' a solid, cylindrical or slightly tapering core made from a material having a high 'conductivity for heat. After applying the first layer of concrete to the core the concrete is externally heated at a temperature causing rapid setting. In a `similar way the second layer. of concrete is heated at a suitable temperature. Finally,

after the whole mass of concrete has set heating is continued at the outside of the pipe, while a coollng medium is applied to the inner side and to the core, so that the core is contracted and made loose from the concrete. p

For the purpose of explaining the invention an example embodying the same has been shown in the accompan ing drawing, in which the same referencecli been used'inall the views to indicate correspondingparts. In said drawing Fig'l, is a sectional elevation showing the core and the concrete applied thereto,

Fig. 2, is a detail sectional elevation showing the bottom part of the `core and concrete and a ring used for removing the set pipo from the core, q

Fig. 3 is a diagrammatic sectional elevation showing the action of cooling of a tube being formed upon a conical form and upon a form having a projectin shoulder at the larger end of the conical orm respectively',

' Fig. 4, is a `somewhat diagrammatical elearacters have vation showing means for heating the concrete applied to the core, A

gig. 5, is a partial plan View of Fig. 4, Fig. 6,'is a detail sectional elevation showing a part of the core and the pipe on an enlarged scale. l

In carrying out my improved process a solid and substantially cylindrical or slightly tapering core is used, which is vertlcall placed on a suitable rotary table, and whie is slowly rotated about-fits vertical axis awhile lnging or squirting soft concrete thereon,l

Aas has been described for example in my copending application for patent, Ser. No.

4,015. While in the method described in the said application a. core 'is used which is made from severa-l sectors, I use an Integral \or solid hollow vcylindricalor slightly tapering core a, by means ot' which a pipe is made which has a very smooth inner surface. -At the end of larger diameter of the said core there is an enlarged annular portion a the outer diameter of which corresponds to the inner diameter'of the usual enlarged portion' of the pipes of this type used for making the pipe joint. herefore the radius of the enlarged port-i a ofthe core exceeds the radius of the adjacent-.portion of the body a of the pipe by the thickness of the wall of the complete 'concrete pipe plus the space requiredA for applying the ordinary ackin medium in the joint. It will be unv erstoo that also the portion a" tapers slightly from the bottom end towards the body a, and that the core from the concrete pipe, as will be described hereinafter,

The core a, a is made from strong andl smooth material having high conductivity for heat. Preferably it consists of a suitable metal such as cast iron. But in some cases I manufacture the same' from concreto having metal chips embedded therein for increasing the conductivity for heat.

The pipe a, a is closed at its top and bottom ends by rigid lids b and b made from metal such as cast iron, and the said lids are coated at one or 'both' sides with layers o ando made from a material of high insulating capacity such as rubber. In some cases I place protective sheets 0, o of metal or* other suitable material on the said layers of rubber. Preferably washers v and o of rubber are placed between the end faces of the 4core a, a and the lids b, b'. i

Suitable means are provided for rigidly connecting the lids b and b to the core a, a. As shown in Fig. 1 a rod 'ui is provided for this purpose. The lib b is formed at nits bottomy face with an axial cylindrical `lug L adapted for en agement with a corresponding socket ma e in the rotary table, and the rod fw is formed at its top end with an eye g for suspending the same from the chain of a hoisting machine.

Through the up er lid Zi pipes c and lc are passed, throug which .a suitable heating or cooling medium may be circulated through the inner part of the core, and in some cases I provide a vent m for removing the air from the core. The lower lid b `is formed with -a discharge opening normally closed by a valve `Z, the stem Z being passed upwardly through the core and carrying at its outer end a nut l for pressing the valve l on its seat.

At their outer sides the` lids b' and b are provided with annular recesses b,l b* having rings d and Ve fitted therein. The outer diameters of the said rings are equal respectively yto the outer diameter of f-the concrete pipe andl the enlarged portion thereof, and they embrace respectively with their top and bottom parts the top and bottom parts of the core a, 0J. Thus the outer portions of thesaid rings determine the thickness of the concrete pipe R and the position of the end facesof the said pipes. 'I he rings d and e are connected with the lids b and b so that they may be readily removed therefrom. To show what may be done arms f are rockinfrly mounted on the lids, which arms are adapted to be turned outwardly for fixing the rings to the lids. In Fig. 1 only one of the said arms is shown.

But I wish it to 'be understoodthat at least 1 three arms are used for each ring d and e. Then turning the said arms inwardly the rings d and e can be readily remoeved.

After constructing the core in the manner described Iplace the same in vertical position on the rotary table and impart slow rotary movement thereto while gradually applying the soft concrete thereto. Apparatus suitable for this purpose has been described in my copending application for patent, Ser. No. 4,015 and I tdeem it not necessary to describe the apparatus in detail. The core may be placed on the said table while being at room temperature. But I prefer slightly to heat the same, for example by shortly immersing the same into Warm water, or filling the same withwarm Water. After the iii-st part of the concrete has been applied the core is perfectly insulated as against loss of heat, the lids being coated with insulating material in the manner described, and the concrete applied to the core a, a having low conductivity for heat. The mass of concrete which is comparatively cold, is uniformly and slightly heated from the core.

After moulding the inner layer of con.,-A crete having a thickness of one half the thickness of the desired wall of the pipe, the said layer of concrete is allowed to set, and in order that the period of time required for setting be reduced I carry the core and the innerv layer of concrete applied thereto into the apparatus shown 1n Figs. 4. and 5, a suitable hoisting machine consisting of a crane K running on a suitable rail G being provided for this purpose. As shown the said apparatus consists of a pit comprising a large chamber A filled with hot water and a plurality of small chambers B. The water contained in the chamber A is heated for example by means of a heating coil I-I toa temperature of from 40 to 60O C. 'Ihe size of the chambers B is comparatively small and it is not larger than .is necessary for receiving the core a, a and the concrete applied thereto. The chambers are heated by the heat transmitted thereto from the chamber A.

After va pipe R and its'core have `been placed into 011e of the chambers B the lid F is closed. The small amount of air Within the said chamber is rapidly saturated with vaporized water, and by reason of the elevated temperature the concrete begins to set after a short period of time. In this process .only a very small amount of thc water of the concrete is vaporized, so that no cracks are produced in the layer of concrete. After a short period of time the concrete has set so far that it ma be exposed to contact with warm water. lid F the core is again elevated by the hoisting apparatus K and carried into the hot herefore, after removing the l 4 the manner described above.

water contained within the chamber A. Within the said water setting is completed within three or four hours. Thereafter the core and the set layer of concrete are carried to the linging apparatus, Where the second layer is applied to the inner layer in the same way as has been described above. If it is desired to manufacture re-inforced concrete pipes I apply the're-inforcing iron to the set inner layer prior to applying the outer layer thereto, the said re-inforcing iron being in the form 4oit a net, a helically wound'wire or strip iron. In Fig. 6 I have shown the core, the inner and outer layers and the reanforcmg iron on a larger scale,

Fig. 1 by the points n, o, p, may be mould# ed by removing the excess o material by cut ting wires While gradually rotating the core.

This method is known in the art and I deem it I lot necessary to describe the same in detai Now the cgre is again carried to the pit A, B, where the outer laye-r is made to set' in Finally the core is removed from the pipe R.

After the core `and the pipe carried by have been removed from they pit A the rings d and e are removed from the lids 'b and b', and the corev and mass of concrete R are placed with the bottom on the hing 7' shown in Fig. 2, so that the'whole mass of the core and pipe bears on the lower end face of the enlarged bottom part of the pipe. In

.- order that the core be more readily placed on the said ring I prefer to form the lid with a bevelled margin s. Now .the hoiawater which may be contained within the hollow oi the core is discharged through the valve Z, and a cooling medium, such as cold water is made to circulate through the said core. Thereby the core L, a is slightly contracted while the concrete pipe R remains at elevated temperature by reason of itsl low conductivity for heat, so that it is not contracted.

T herefore the core is made loose from the Evidently the core is contracted not only in circumferential direction but also in axial direction. By reason of the shoulder t of the core the body a is contracted downwardly. The length of the pipe being about three meters, there is anappreciableA longitudinal displacement of the core a relatively to the pipe R, which assists in disconnecting the therecore from the pipe. I have found that ordinarily the -core is automaticallyr disconnected from the pipe, and that a slight blow made with a hammer is sufficient to remove the core from the pipe without injuring the latter. In order that the core be more readily separated from the pipe I provide the same with a very smooth surface, and in some cases I apply thereto a suitable medium such as oil, graphite or the like prior to applying the inner layer of concrete thereto.

It will be understood that in the manufacture of the pipes each core is used several hours for making a single pipe. Therefore, when using cores made from metal the cost 'of the stock of cores is very high. In order to reduce the cost I prefer 'to .manufacture the cores from' concrete having a high couductivity for heat, so that only the lids b, bf and the rings'd, care made from metal. In the practice of this part of my invention I manufacture a tubular mould from any suitable material, the inner configuration of which exactly corresponds to tl e inner form ofthe concrete pipe R and I p acc a core of metal or wood into the said pipe, which corresponds to the inner diameter ofthe cor(-- d, a. The mould thus formed is filled with concrete having metal chips admiXed thereto, and I allow the said concrete to set in the ordinary Way. The concrete pipe a, 'af 'which has thus been manufactured is used in the manner described above. Should the concrete core a, a be injured after some time of use it may be replaced at low cost, while the lids b, b and other metal parts may be used for any length of time.

The separat-ion of the core from the concrete pipe may be further accelerated by externally heating the pipe R While. internally 'i cooling the core. For example, I place the core and pipe on the ring within a pit similar to A or Within the pit A itself, so that the pipe is heated by the warm Water. contained within the said pit. Further, means may bet-provided for fillinghe chambers B with Warm water after heating the pipe by means of air, and to return the hot water at the end of the setting process into the chamber A. Nhen thus carrying out the process it is not necessary to carry the core from the chamber B into the chamber A. Apparatus for carrying out this) modification of my method will readily suggest themselves to those skilled in the art, and I deem it not necessary to show the same in the drawings.

While in' describing the invention reference has been made to particular examples embodying the .same I wish it to be understood that I do notV limit myself to the particular method and the apparatus described herein.

Iclaim:

1. The herein described method of manufacturing pipes from plastic matter, which l lll) fri

\ plastic matter containing cement to a core,

allowing the said plastic matter to set, applying a thin layer of the said plastic matter to the setv matter, applying re-inforcing iron l'on the said thin layer ,while soft, applying -f another layer of the said plastic matter to the iron, and allowing the same to set, the thickness of the layers first and last applied being substantially equal to one half the thickness of the wall of the pipe to be made.

3. A mould for manufacturing pipes from plastic matter containing cement, comprising an integral tubular core, lids fixed to thc end faces of said core and having a diameter equal to the outer diameter of said core, and

rings fixed to said lids and foi-ined with flanges embracing the ends of said core and having a diameter equal to the outer diaiiieter of the pipe to be manufactured.

4, A mould for manufacturing pipes from plastic matter containing cement, comprising an integral tubular tapering core formed 'at the end of larger diameter with an enlarged' annular portion, disks fixed to the end faces of said core and having diameters equal to the outer diameters of the adjacent portions of the core, and rings fixen-to said lids and formed with flanges embracing the ends of thecore and having outer diameters equal to the outer diameters of the adjacent portions of the pipe to be manufactured.

5. The herein described method of manufacturing pipes which consists in applying plastic matter containing cement to a core, allowing the said plastic matter to set, applying a thin layer of the said plastic matter -to the set matter, applying reinforcing helically wound Hexible elongated iron on the said thinllayer while soft, applying another layer of the said plastic matter to the iron, and allowing the same to set, the thickness of the layers first and last applied being substantially equa] to one halfthe thickness A of the Wall of the pipe to be made.

In testimony whereof I have atiixed my,

signature.

ALPHONS HORTEN. 

